Paleontologists have discovered the oldest fossilized tracks of a reptile-like animal in Victoria, Australia, dating back to the early Tournaisian age, around 355 million years ago. The find suggests that such animals originated in the southern supercontinent Gondwana, where Australia was part of.
The discovery sheds light on the evolution of tetrapods, which emerged from a group of fish about 390 million years ago during the Devonian period. These early tetrapods became the ancestors of modern backboned land animals, including amphibians and amniotes, such as mammals, reptiles, and birds.
The oldest known amniote fossils were found in the later Carboniferous period and date back about 320 million years. The new discovery is significant because it pushes the evolution of these reptile-like creatures back by at least 35 million years, making them one of the earliest evidence of land-walking animals.
Researchers Flinders University’s John Long, Uppsala University’s Grzegorz Niedźwiedzki, and Per Erik Ahlberg identified the track-bearing slab as belonging to an animal that resembled a small, stumpy goanna-like creature. The team notes that claws are present in early amniotes but rare in other tetrapods.
The discovery has profound implications for our understanding of tetrapod evolution. Previous thought was that all stem-tetrapod and stem-amniote lineages originated during the Devonian period, but new evidence suggests that tetrapod evolution proceeded at a faster rate, with a more incomplete record from the Devonian era.
According to the team, fossilized trackways provide valuable insights into an animal’s behavior. The early Carboniferous trackway discovered in Victoria provides significant information about the movement of these ancient creatures.
“This discovery rewrites this part of evolutionary history,” said La Trobe University’s Jillian Garvey. “It indicates that there is still much to be uncovered in Australia and Gondwana.”
Source: https://www.sci.news/paleontology/earliest-amniote-tracks-13910.html